Question

A converging lens has a focal length of 20 cm is in air. It is made of a material of refractive index 1.6. It is immersed in a liquid of refractive index 1.3. Calculate its new focal length.

Answer 1

Answer:

Explanation:

1/20=(1.5-1)(1/R1+1/R2)

according to second condition

1/f=(1.5/1.3/-1)(1/R1+1/R2)

after dividing both equations u will get answer